The invention relates to a tracheostomy tube, particularly a tracheostomy tube which is percutaneously inserted between two adjacent cartilages into the trachea of a patient, to assist breathing.
Tracheostomy tubes have been used for some time to provide a bypass supply of air or mixture of gases to a patient having an obstruction in the throat. The distal end of the tracheostomy tube is inserted into the trachea through an incision in the patient's neck below the obstructed area. The proximal end of the tube remains outside the trachea in communication with ambient air to permit passage of such air into the trachea. The proximal end can also be attached to a respiratory device to assist the patient's breathing. The distal end can also include an expandable cuff for forming a seal between the tracheostomy tube and the tracheal wall of the patient to further facilitate breathing on the respiratory device. During operative "standard" tracheostomy, a vertical incision of about 5 cm is made in the mid-line of the neck in the vicinity of the trachea. Cartilages are severed with portions thereof sometimes removed and a relatively large stoma is created for the insertion of the standard tracheostomy tube. The operative procedure usually requires an operating room, general anesthetic and can take 45-60 minutes to perform. The operative procedure further requires transportation to and from an operating room and, due to the surgical stoma, can sometimes lead to infectious complications and cosmetic deformity.
In some installations of tracheostomy type devices, it is possible to insert the device by a technique known as percutaneous insertion. This technique was introduced by Dr. Seldinger in his wire-guided approach to arterial catheterization, and has been widely adapted to other application to include: the placement of trans-tracheal oxygen catheters, tube nephrostomy, drainage of abnormal fluid collections, and epidural catheterization for antiseptic purposes.
One recently described application of the Seldinger technique has been for percutaneous tracheostomy as described in a preliminary report by Dr. P. Ciaglia, et al entitled, "Elective Percutaneous Dilatational Tracheostomy: A New Simple Bedside Procedure" published in Chest Volume 87: 715-719, 1985. The technique is considered to be rapid, technically simple, and remarkably free from technical complications. The brief highlights of the technique include first, a small (about 1 cm) insertion is made below the lower edge of the cricoid cartilage. In conjunction with a local anesthetic, a syringe with an over-the-needle cannula is inserted through the incision into the tracheal lumen. The syringe is then removed and a flexible J-wire guide is inserted and extended downwardly into the trachea. The cannula is then withdrawn and a catheter guide is inserted followed by a series of increasing diameter dilators which are inserted over the guide to expand the stoma. The dilators are removed and a standard tracheostomy tube with one of the dilators used as an inner obturator is then inserted over the guide and into the trachea. The obturator and guide are then removed and the tracheostomy tube is secured to the patient. The various components, as described in the publication by Dr. Ciaglia, to include: the catheter introducer needle, the J-wire guide, dilator, and a series of six increasingly larger curved dilators (12 Fr. to 32 Fr.) have been packaged as "A Percutaneous Tracheostomy Introducer Set" available from Cook Inc., Bloomington, Ind., for percutaneous installation of standard tracheostomy tubes. The components are in a "peel-away" pack which must be opened and then arranged on a surgical tray, along with the preparation components and tracheostomy tube which are not provided.
An Emergency Cricothyrotomy System is described in U.S. Pat. No. 4,677,978 by Richard Melker which incorporates the Dr. Ciaglia method between the thyroid and cricoid cartilages with insertion of a relatively small (5.5 mm inner diameter) air passage catheter (which does not have an inflatable sealing cuff) into the patient.
Another type of tracheostomy device and procedure is disclosed in Jacob's U.S. Pat. No. 3,682,166 and U.S. Pat. No. 3,788,326. A small, flexible, curved catheter described therein is placed over a 14 or 16 gauge needle and is percutaneously inserted through the crico-thyroid membrane at about a 45.degree.-60.degree. angle The needle is withdrawn and the catheter is secured for transtracheal ventilation. The device and procedure are described in more detail in the publication by Dr. Jacobs et al entitled, "Transtracheal Catheter Ventilation: Clinical Experience in 36 Patients" and published in Chest, Volume 65, No. 1, January 1974, pp. 36-40.
Another somewhat related device is disclosed in U.S. Pat. No. 3,538,918 by Engelsher et al, in which a tracheo-bronchostomy tube assembly includes an outer tube and an inner tube, in which the outer tube is percutaneously inserted. The outer tube is described and illustrated as having a distal end with a bevel toward the rear of the tube. The longer inner tube is telescopically inserted into the outer tube to facilitate the removal of secretions from the broncheal passages.
A recurring problem with all of the known tracheostomy tubes of the prior art is the tendency of the distal end of the cannulae to interfere or catch on the tracheal cartilage as the tube is pushed into the trachea. Typical commercially available tubes have a distal tip which is either blunted, straight with a small annular taper or radius, beveled to the rear of the patient, or beveled to the front of the patient. For percutaneous insertion, none of these configurations are consistently free from interference with either the upper cartilage or the lower cartilage or both as the distal end of the tracheostomy tube is forced between the adjacent cartilages.